Pen holder



FIG. 1 is a perspective view of a pen holder showing my new design;

FIG. 2 is a top plan view;

FIG. 3 is a bottom plan view;

FIG. 4 is a left side elevational view;

FIG. 5 is a right side elevational view;

FIG. 6 is a front elevational view; and

FIG. 7 is a rear elevational view. 

The ornamental design for a pen holder, substantially as shown. 